A type of sexuality where one person being so deep in love or obsession can only be attracted to/aroused by a single person not even other men, or, for that matter, women. Not even porn can do it for them, unless his/ her lover is in the porn. If the lover changes gender, he/she will still be hot for them.

Sometimes it gets to the point where he/she becomes a Stalker with a Crush or something similar.